This invention relates in general to sewing machines and in particular to a new and useful attachment for feeding reinforcing back buttons to a sewing machine which has a feed for main buttons to a button clamp which is positionable over the work material.
Simultaneous sewing of a main button to the upper side and of a back or reinforcing button to the underside of a piece of clothing is known, for example from German Pat. Nos. 668 456 and 699 972. The receiving element for the main button is a liftable button clamp, while a recess in the workplate is provided for the back button. Both buttons must be brought into alignment and placed in the receiving elements by the operator.
In machines of this kind, more than enough space is available for the piece of clothing above the receiving element. That is why automatically operating devices for aligning and feeding the main button have been developed, see for example U.S. Pat. No. 3,157,311 and German Utility Model No. 75 38 335. In the U.S. device, the buttons are directed from a supply receptacle connected to a vibrator, through a chute to a brake which must be released upon lifting the bottom clamp, to clear the feedway and let the leading button in the fed row slide under its own weight into the sewing position determined by the pivotally mounted stop. This, however, can be done only with buttons of a definite shape such as the button provided in the U.S. reference, having an about rectangular extension and thus capable of self-aligning, if the feed channel is adequately designed. In the device disclosed in the German reference, the buttons are brought into their sewing position by means of aligning and feed mechanism.
If a back button is to be sewed simultaneously with the main button in such prior art devices, the back button must still be aligned and put in place in the receiving element manually, because the space beneath the piece of clothing is too limited to allow a mounting of aligning and feeding mechanisms. Losses of time are therefore unavoidable, since the work must be removed whenever a back button is to be inserted. It is not possible either to use time-saving tabulators, by means of which upon every sewing operation, the work is automatically shifted through the spacing between two buttons.